This invention relates to a new instantized/agglomerated pregelatinized (either cold water swelling or traditional pregel) starch and to its preparation and use in the preparation of a variety of products requiring complete starch dispersion and rapid viscosity development with little or no stirring. Among these products are foodstuffs such as thickened foods for dysphagia, instant dry mix desserts and pie fillings, instant beverages for the nutritional and functional food segments, dry mix soups & sauces, whipped toppings and similar processed food products. These products and others can be improved due to the presence of a category of instantized/agglomerated pregelatinized starch products with new properties.
Starch is known to become functional for rheologically altering the viscosity characteristics of various products, including but not limited to foods, only after being cooked in aqueous slurry beyond a critical temperature (i.e., the pasting temperature) such that the granules hydrate, swelling many times their original size. It is further known that the needs of the food industry dictate that starch often be precooked or pregelatinized so that viscosity and texture can be altered without the use of heat in the process. These pregelatinized starches are problematic in that in the powdered form they have a tendency to form undispersible lumps when introduced into aqueous systems. The process of agglomeration of these starch powders has mitigated this problem to a great extent but not without adversely impacting the performance of the end product.
One of the major disadvantages of agglomerated starches in the current markets is that the rate of hydration is too slow. When the starches are added to aqueous solutions, especially chilled ones such as milk, apple juice, etc., starches swell at slow speed and do not reach maximum viscosity until as long as half an hour, depending on starches and liquid medium. Another disadvantage is that they often result in an unusually coarse or pulpy appearance and texture being imparted to the finished food product by the agglomerated starch. In cases where a smooth appearance and texture is desirable, this is a definite drawback.
It would be desirable if there were instant food thickeners, especially in the medical-nutritional and spoon stirred beverage, soup, sauce and gravy markets, that dispersed without lumping yet attained maximum viscosity within a very short period of time (e.g., in less than five minutes). If available, such food products with instantly dispersible pregelatinized starches would have clear and significant processing and economic advantages.
The prior art has produced a number of starches that are suitable for use in instant food thickeners and sugar-free desserts, but dispersibility is often sacrificed to maintain a desired viscosity development. To date, means have been developed that circumvent these pit-falls such as the co-agglomeration of a starch with the food products in question, utilizing the bulk of the food product as a dispersing aid for the starch. This is an added cost to the food manufacturer and is not a suitable solution for the medical-nutritional food thickener market. Prior art starches have also failed to be successful in the commercial world where they have provided an improvement in initial dispersibility which is not stable over time due to chemical or physical changes in the starch composition. There is currently no product that offers all of the advantages of rapid dispersibility, rapid viscosity development and smooth appearance and texture. Current products all have serious compromises or lose these properties over time.
In an early attempt to make instant pudding compositions, U.S. Pat. No. 2,554,143 to Hinz, Jr., et al., describes a process to decrease lumping of the pudding upon addition of aqueous liquid. They set out to improve upon the instant puddings of Hinz, Jr., et al., in U.S. Pat. No. 2,500,179, which required a fine particle size for the starch to be satisfactorily smooth, but became lumpy when hydrated. They coat the starch particles with an oleaginous agent to inhibit hydration. Among the materials they suggest as coating agents are fats, oils and waxes. They apply the coatings at levels of up to about 10%. The oleaginous substance is applied in a milling operation following micropulverization. Experience with these types of products has not been fully satisfactory because they tend to have slow viscosity development and low viscosity levels, probably because the coating of the fatty material retards hydration. In addition, these materials tend to be unstable as wetability and dispersibility vary over time.
In another prior art approach, in U.S. Pat. No. 3,443,900, Decnop disclosed that a dry hydrophobic reaction product of cold water dispersible starch with a finely divided monoglyceride and/or diglyceride prior to heating and drying treatment. The same reaction between the monoglyceride and/or diglyceride and the amylose helix of the starch to which they attribute improved dispersibility is believed to continue unevenly on storage to result in products of variable quality. Here again, experience has not been fully satisfactory because these products tend to have slow viscosity development and low viscosity levels, and they tend to be unstable with wetability and dispersibility varying over time.
The problem of making an instantly dispersible pregelatinized starch composition was also addressed by Werbin, et al, in U.S. Pat. No. 3,582,350. They described a process wherein a pregelatinized flour or starch was suspended in aqueous slurry, mixed with a hydrophobic shortening material or blend with emulsifier, and subjected to a brief heat treatment at elevated temperature. Again, these products do not show a desired degree of dispersibility exhibiting stability over time.
Over the years, the quest for a high quality instant pudding provided incentive for research into ways to achieve a starch product suitable for use in instant puddings to provide excellent texture, creaminess, and mouth release effect. Among the efforts was the disclosure of U.S. Pat. No. 4,215,152, to O'Rourke, who taught making such a product by a process that comprises drum drying a slurry containing an ungelatinized starch in water with a protein and an emulsifier. Preferably the protein is sodium caseinate and the emulsifier is polysorbate 60. Similarly, In U.S. Pat. Nos. 4,260,642 and 4,362,755, Mitchell, et al., describe a process for preparing a pregelatinized modified starch suitable for use in instant puddings which comprises forming an aqueous slurry containing an ungelatinized starch and an effective amount of sodium or calcium stearoyl-2-lactylate, heating the slurry to a temperature and for a period of time sufficient to gelatinize the starch, and recovering the starch. The resultant pregelatinized modified starch is said to possess a smoother, creamier mouthfeel and has a high sheen.
Still in the context of dry instant pudding mixes, in U.S. Pat. No. 4,469,712, Katcher, et al., describe a process for providing puddings with improved texture and gloss, by incorporating a critical starch particle size distribution with a powdered sugar of a controlled particle size. They point out that U.S. Pat. No. 4,361,592 issued to Carpenter, et al., describes a pudding mix composition which, when combined with milk, produces a desirable, creamy, glossy pudding. Carpenter, et al., was said to teach that it is critical to making a glossy, creamy pudding with fine particles of pregelatinized starch that less than a maximum of 1%, by weight, of the starch has a particle diameter greater than 63 microns and that commercial pregelatinized starch at that time did not meet the requirements of Carpenter, et al., without further processing. They further state that Carpenter, et al., necessitates recycling the starch particles—sieving, and regrinding—thereby increasing the cost of production. They pointed out that U.S. Pat. No. 2,554,143 issued to Hinz, Jr., et al., teaches that fine starch particles can be used in an instant pudding mix, only if their rate of hydration is retarded such as by coating the starch with a hydrophobic material, such as a lipid or talc. As an alternative, Katcher, et al., described what they characterized as a new critical aspect that the total starch particle distribution wherein the vast majority of the starch particles have diameters smaller than 38 microns.
In another prior art attempt to improve the properties of pregelatinized starches, U.S. Pat. No. 4,575,395 to Rudin describes a process for producing a coated pregelatinized starch comprising blending a pregelatinized starch with a mixture of a non-toxic solvent and a food grade emulsifier followed by removing the solvent. Listed among the emulsifiers are a mixture of distilled propylene glycol monoesters, distilled monoglycerides, and sodium stearoyl lactylate, hydrophilic ethoxylated sorbitan monoesters, lecithin, monoglycerides, diglycerides, and mixtures. They also list a number of sugars and other carbohydrates. Suitable solvents are said to include ethanol, mixtures of water and ethanol, mixtures of water, ethanol and ethyl acetate whereby the ethyl acetate is present in small quantities such as a denatured ethyl alcohol.
In U.S. Pat. No. 4,726,958, Brown, et al., describes a process for producing an instant no-bake filling mix which upon reconstitution or hydration is said to have a glossy, smooth, creamy and firm texture with a sliceable pie cut characteristic on setting. The pre-filling mix is made by mixing all dry ingredients and then incorporating fat or oil, in a process said to be distinguished from those of Carpenter, et al, O'Rourke, Hinz, et al., and Rudin, all cited above, and others.
In U.S. Pat. No. 4,769,081, Maher describes enhancing the rate and ease of water dispersibility and/or water solubility of powdered or granular starch materials suitable for use various industrial end-use applications such as, for example, in paper sizing applications, as a wet end dry strength additive, in pigmented paper coating compositions, in packaging adhesive applications, in size press applications, in binder compositions, in textile sizing and finishing applications and the like. They achieve this by incorporating a small amount of a glycoside surfactant ingredient. Maher identifies as starch materials of particular interest, the various cold water-soluble pregelatinized starches, particularly pregelatinized potato starch and especially pregelatinized cationic potato starches. A glycoside and potato starch combination is exemplified as dry blending 50 parts by weight of a potato starch with 0.005% of a 50% solution of a C12-13 alkyl glucoside surfactant having an average degree of polymerization of about 1.8. Their applicability to food products is not suggested or apparent.
In U.S. Patent Publication No. 2002/0014180, Marie, et al., describe another approach to preparing starch based dry mixes. They describe an agglomerated starch-based product which is a homogeneous powder wherein each powder particle is an agglomeration of randomly distributed fine grains of starch and maltodextrin. The agglomerated starch-based product is said to be readily dispersible in aqueous fluids and develops its full viscosity instantaneously. The maltodextrin used is a polymeric hydrophilic compound, being a glucose polymer, with a dextrose equivalent (DE) of less than 20, preferably a maltodextrin with DE not higher than 16, more preferably with DE of from 5 to 15 is applied. The maltodextrin is present in an amount of from 5% w/w to 95% w/w on dry base of the agglomerated starch-based product, preferably from 10% w/w to 75% w/w, and more preferably from 15% w/w to 50% w/w, most preferably in an amount of from 15% w/w to 40% w/w.
Thus, the art has long sought a suitably dispersible cold water-soluble starch that rapidly and fully disperses to achieve its potentially full viscosity within a very short period of time. However, the art is in need of improvement in terms of products, processes and their end uses which more fully meet the objectives of the art than heretofore achieved.
There remains a need in the art for instant/agglomerated pregelatinized starches that can be spoon stirred into solution hot or cold without the formation of lumps and that develop maximum viscosity in a very short amount of time and yet are shelf stable in terms of these properties.